KR101383532B1 - Wavelength-converting resin composition for solar cell, and solar cell module - Google Patents

Abstract

When the wavelength converting resin composition for solar cells contains the fluorescent substance whose maximum absorption wavelength of the absorbance spectrum is (lambda) _max (nm), resin particle, and a dispersion medium resin, and forms the resin film of thickness (t (micrometer)), , The intensity of the transmitted light obtained by incidence of incident light having an optical intensity of I ₀ (λ) is set to I (λ), and the thickness of the reference resin composition excluding the fluorescent substance and the resin particles from the resin composition is t _ref (μm). In the case where the intensity of the transmitted light obtained by entering the resin film for reference is I _ref (λ), the value of A ₁ (λ) represented by Equation 1 is 3.0 × 10 ^{− at the} maximum absorption wavelength λ _max (nm). ^It is comprised so that it may be ⁴ (OD / micrometer) or less.
Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref

Description

WAVELENGTH-CONVERTING RESIN COMPOSITION FOR SOLAR CELL, AND SOLAR CELL MODULE

The present invention relates to a wavelength convertible resin composition for a solar cell and a solar cell module.

In the conventional silicon crystal solar cell module, the protective glass (also called cover glass) on the surface is made of impact resistance and tempered glass is used, and a sealing material (typically a resin mainly composed of ethylene-vinylacetate copolymer), In order to improve the adhesiveness with respect to the filler), one side is provided with an uneven shape by embossing. Moreover, the uneven | corrugated shape is formed in the inside, and the surface of a solar cell module is smooth (the uneven | corrugated shape may be given also on the outer side in order to raise the efficiency of solar light introduction). Moreover, the sealing material and back film for protecting and sealing a solar cell, a tab wire are formed in the lower side of protective glass.

By the way, various proposals are made | formed in order to improve the power generation efficiency of a solar cell. For example, Japanese Patent Application Laid-Open No. 2000-328053, Japanese Patent Laid-Open No. 2001-352091, and the like use a fluorescent material and convert wavelengths of light in an ultraviolet region or an infrared region having a low contribution to power generation in the solar spectrum. A method of forming a layer on the solar cell light-receiving surface side that emits light in a wavelength region having a significant contribution to power generation has been proposed.

In the proposals of JP 2000-328053 A and JP 2001-352091 A, the wavelength conversion layer converts light in a wavelength region with a small contribution to power generation into light in a wavelength region with a large contribution to power generation. It contains a substance, which generally has a large refractive index, and from that shape, the incident solar light is scattered when passing through the wavelength conversion film and does not reach the solar cell sufficiently, thereby increasing the rate of not contributing to power generation. There was a case.

An object of this invention is to provide the solar cell module provided with the wavelength conversion resin composition which can comprise the solar cell module which is excellent in power generation efficiency, and the light transmission layer containing this wavelength conversion resin composition.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, in the conventional wavelength conversion layer, since the fluorescent substance which differs in refractive index from a medium, and large particle diameter is disperse | distributed to the transparent dispersion medium resin, light scattering arises and a wavelength conversion layer We found that the conversion of light in the ultraviolet region into visible light does not improve the ratio of power generated to the incident sunlight (power generation efficiency). In addition, even if there is no light loss such as scattering in visible light, even if scattering can occur in the light in the ultraviolet region, even when the wavelength conversion function has a negative effect on the conversion efficiency of the solar cell. I have found that. Based on these findings, when the light is scattered in the wavelength conversion resin composition which converts the light of the wavelength range of the incident sunlight which has a small contribution to photovoltaic power generation into the light of the wavelength which has a big contribution to photovoltaic power generation, There was little, and the method used as the judgment standard which can be efficiently introduced into a solar cell was found out, and the present invention was completed.

That is, the present invention is as follows.

<1> as a fluorescent material is maximum absorption wavelength in the absorption spectrum λ _max (㎚), a resin particle and a resin composition containing a dispersion medium, the resin, the light intensity at a wavelength λ (㎚) I ₀ (λ ), The intensity of the transmitted light obtained by incident phosphorus incident light in the thickness direction of a resin film having a thickness of t (µm) is set to I (λ), and the incident light is removed from the resin composition except the fluorescent substance and the resin particles. The value of A ₁ (λ) represented by the following formula 1 when the intensity of the transmitted light obtained by incidence in the thickness direction of the reference resin film whose thickness formed of the resin composition for reference is t _ref (μm) is set to I _ref (λ). The wavelength convertible resin composition for solar cells which is 3.0 * 10 <^-4> (OD / micrometer) or less in this said maximum absorption wavelength (lambda) _max (nm).

Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref

<2> The said fluorescent substance is the wavelength convertible resin composition for solar cells as described in said <1> contained in the said resin particle.

<3> The said fluorescent substance is a wavelength convertible resin composition for solar cells as described in said <1> or <2> which is a rare earth metal complex containing an organic ligand.

<4> The solar cell module provided with the light transmissive layer containing the wavelength convertible resin composition for solar cells in any one of said <1>-<3>.

As an evaluation method of the wavelength converting resin composition for solar cells containing the fluorescent substance whose maximum absorption wavelength in a <5> absorbance spectrum is (lambda) _max (nm), and a dispersion medium resin, the light intensity in wavelength (lambda) (nm) is It joined to the resin layer in the thickness direction I ₀ (λ) of incident light to the resin composition having a thickness of t (㎛) formed from and the intensity of transmitted light is obtained by I (λ),

In the case where the intensity of the transmitted light obtained by inciting the incident light from the resin composition in the thickness direction of the reference resin film having a thickness of t _ref (μm) formed from the resin composition for reference except the fluorescent substance is I _ref (λ), the maximum absorption wavelength λ _max (㎚) of the formula 1 ₁ a solar cell wavelength conversion evaluation methods of the resin composition, comprising: evaluating the wavelength conversion efficiency on the basis of the value of (λ) represented by in.

Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref

According to this invention, the solar cell module provided with the wavelength convertible resin composition which can comprise the solar cell module excellent in power generation efficiency, and the light transmitting layer containing this wavelength convertible resin composition can be provided.

1 is a graph showing an example of the relationship between the A ₁ (λ) value at a wavelength of 350 nm and the power generation efficiency of a solar cell according to the present invention.
2 is a graph showing an example of the relationship between incident wavelength and A ₁ (λ) value at a wavelength conversion-sensitive resin composition of the Examples and Comparative Examples of the present invention.
3 is a graph showing an example of the relationship between incident wavelength and A ₁ (λ) value at a wavelength conversion-sensitive resin composition of the Examples and Comparative Examples of the present invention.
4 is a graph showing an example of an excitation spectrum and an emission spectrum of a fluorescent material according to an embodiment of the present invention.
5 is a graph showing an example of an absorbance spectrum of a fluorescent substance dispersed in a dispersion medium resin according to an embodiment of the present invention.
Figure 6 is a graph showing an example of the relationship between the generation efficiency of the solar cell and the average value of A ₁ (λ) value at a wavelength of 350 ~ 400 ㎚ related to an embodiment of the present invention.
7 is a graph showing an example of the relationship between the linear transmittance in the visible region and the power generation efficiency of the solar cell according to the comparative example of the present invention.
8 is a graph showing an example of the relationship between the integrated emission intensity and the power generation efficiency of a solar cell according to a comparative example of the present invention.

In this specification, "-" shall show the range which includes the numerical value described before and after that as a minimum value and a maximum value, respectively.

<Wavelength converting resin composition for solar cells>

The wavelength convertible resin composition for solar cells of this invention contains the fluorescent substance whose maximum absorption wavelength in a light absorption spectrum is (lambda) _max (nm), a resin particle, and a dispersion medium resin. In addition to the wavelength λ (㎚) the intensity of transmitted light I (λ) obtained light intensity is incident to the incident light is I ₀ (λ) in the resin composition is a resin film thickness direction and having a thickness of t (㎛) formed with in the And the intensity of transmitted light obtained by inciting the incident light from the resin composition in the thickness direction of the reference resin film having a thickness of t _ref (μm) formed of the reference resin composition excluding the fluorescent substance and the resin particles as I _ref (λ). In one case, the value of A ₁ (λ) represented by the following formula 1 is 0.0003 (OD / μm) or less in the maximum absorption wavelength λ _max (nm).

Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-log {(I ₀ (λ) / I _ref (λ))} / t _ref

The wavelength convertible resin composition for solar cells containing the fluorescent substance, the resin particle, and the dispersion medium resin has an A ₁ (λ) value represented by the above formula 1 in the maximum absorption wavelength λ _max (nm) of the absorbance spectrum of 3.0 × 10 ^−. By constructing so that it may be ⁴ (OD / micrometer) or less, the power generation efficiency in the solar cell provided with the light transmissive resin layer formed from such a wavelength conversion resin composition improves. On the other hand, in the maximum absorption wavelength λ _max (nm) of the absorbance spectrum, when the A ₁ (λ) value represented by Equation 1 exceeds 3.0 × 10 ⁻⁴ (OD / μm), the power generation efficiency does not improve, and power generation Efficiency may fall.

For example, this converts light in a wavelength region having a small contribution to solar power generation into sunlight in a solar cell incident to the solar cell, and efficiently and efficiently suppresses scattering of solar light. It can be considered that this is because solar light can be stably used for power generation.

In the present invention, the A ₁ (λ) value is 3.0 × 10 ⁻⁴ (OD / μm) or less in the wavelength λ _max , but is preferably 2.5 × 10 ⁻⁴ or less, and 2.0 × 10 from the viewpoint of the conversion efficiency of the solar cell. It is more preferable that it is ^10-4 or less.

In the present invention, the A ₁ (λ) value is a diffraction grating type spectroradiometer LS-100 for ECO Co., Ltd. solar simulator, and Wakomu Electric Co., Ltd. solar simulator WXS-155S-10, AM1.5G. Is measured using.

Specifically, the specimen for evaluation was put on the detection part of the diffraction grating type | mold spectroradiometer LS-100, the light was irradiated using the Wakomu electric window solar simulator WXS-155S-10, AM1.5G, and intensity | strength was carried out. The spectrum I (λ) is obtained. Further, nothing is placed on the detection unit of the LS-100 to obtain the intensity spectrum I ₀ (λ) of the blank. Further, the reference specimen is placed on the detection unit of the LS-100 to obtain the intensity spectrum I _ref (λ) of the reference specimen. Using the intensity spectrum measured in this manner, the A ₁ (λ) value is calculated according to the equation (1).

The absorbance spectrum of a fluorescent substance can be measured by a conventional method using a spectrophotometer (For example, Hitachi Hi-Tech Co., Ltd. U-3310, Nippon Spectroscopy Co., Ltd. V-570 etc.).

The thickness of the resin film is measured using a digital micrometer.

In this invention, since the power generation efficiency of the solar cell in a wavelength conversion resin composition is evaluated based on the scattering degree of the light in the wavelength range with little contribution to photovoltaic power generation, in the said (lambda) _max Instead of the A ₁ (λ) value, it may be evaluated by a value correlated with this. Specifically, the following method is mentioned, for example.

In the A ₁ (λ) value of A ₁ (λ) value, instead of the solar cell by using the average value of A ₁ (λ) value in a specific wavelength range including a λ _max in at the λ _max in the present invention Conversion efficiency in the case of a structure can also be evaluated. As a specific wavelength range in that case, it is preferable to make it into the wavelength range of 300 nm or more, and the raise (absorption threshold value) of an absorbance spectrum, for example, and wavelength (lambda) is lambda _max or more, and {log (I ₀ It is more preferable to set it as the range of wavelength (lambda) whose value (absorbance per film thickness) of ((lambda) / I ((lambda)))} / t is 0.0001 (OD / micrometer) or more.

In addition, the value A ₁ (λ) When evaluated as a mean value of a specific wavelength range, A ₁ (λ) value is more preferable that preferably is less than 1.5 × 10 ^-4, and, 1.2 × 10 ^-4 or less, and More preferably, it is 1.0 * 10 <^-4> or less.

And again in the present invention, the conversion efficiency of the case using an integrated value of A ₁ (λ) in a specific wavelength range including a λ _max in place of A ₁ (λ) value at λ _max configured a solar cell You may evaluate. The specific wavelength range in the case of evaluating as an integrated value of A ₁ (λ) is the same as above.

In the case of evaluating an integrated value of A ₁ (λ) in a specific wavelength range, and preferably is the integral of the A ₁ (λ) in a specific wavelength range that is less than 7.0 × 10 ^-3, 6.0 × more it preferred that less than 10 ^-3, and 5.0 is more preferable that not more than × 10 ^-3.

And again in the present invention, also it is evaluated by using the A ₂ (λ) value represented by the following formula (2) in place of A ₁ (λ) value represented by the formula 1 is also preferred. Generally, the A ₁ (λ) value and the A ₂ (λ) value are theoretically equivalent, and the A ₁ (λ) value or the A ₂ (λ) value can be appropriately selected and evaluated according to the available measuring apparatus.

Equation 2: A ₂ (λ) = a (λ) / t − a _ref (λ) / t _ref

In formula (2), a (λ) is the absorbance of the resin film obtained by injecting incident light having a wavelength of wavelength λ (nm) in the thickness direction of a resin film having a thickness of t (μm) formed of the resin composition, and a _ref (λ) Is the absorbance of the said resin film for reference obtained by injecting the said incident light from the said resin composition in the thickness direction of the reference resin film which is thickness t _ref (micrometer) formed from the resin composition for reference except the said fluorescent substance and resin particle.

A ₂ (λ) value in the present invention, in view of the conversion efficiency of the solar cell, and the wavelength λ _max is ^{3.0 × 10 -4 (OD / ㎛} ) or less, more preferably not more than 2.5 × 10 ^-4 And it is more preferable that it is 2.0 * 10 <^-4> or less.

In A ₂ (λ) value in the present invention may be evaluated as an average value of A ₂ (λ) value in a specific wavelength range including a λ _max to A instead of ₂ (λ) value at λ _max, as needed have. In a specific wavelength range in this case is, for example, λ _max or more, and increase in the absorption spectrum (the absorption threshold) to a to the wavelength range, preferably of, and the wavelength λ λ _max or more, and a (λ) / It is more preferable to set it as the range of wavelength (lambda) whose value of t is 0.0001 (OD / micrometer) or more.

In the wavelength converting resin composition of the present invention, as a specific method of configuring the A ₁ (λ) value (or A ₂ (λ) value) to be within a predetermined range, for example, a fluorescent substance is contained in the resin particles. The transparent substance which can disperse | distribute the fluorescent substance coated with the polymeric dispersing agent obtained by disperse | distributing this thing to the dispersion medium resin which can disperse | distribute this, and a wavelength converting resin composition, and disperse | distributing fluorescent substance using a polymeric dispersing agent The method of disperse | distributing to a dispersion medium resin, and the method of simply lowering the content rate of fluorescent substance are mentioned. In the present invention, from the viewpoint of power generation efficiency, it is preferable that the fluorescent material is contained in the resin particles or the method of using the fluorescent material coated with the polymer dispersant.

In addition, the detail of these methods is mentioned later.

(Fluorescent material)

The fluorescent substance used in the present invention is not particularly limited as long as it is a compound capable of converting light out of the wavelength range available in a conventional solar cell into a wavelength range available in a solar cell. For example, the rare earth metal complex containing an inorganic fluorescent substance, an organic fluorescent substance, an organic ligand, etc. are mentioned.

The inorganic fluorescent substance is, for example, Y ₂ O ₂ S: Eu, Mg, fluorescent particles of Ti, Er ^{3 +} ions by fluoride-based crystallized oxide-containing glass, a rare earth element to a compound consisting of strontium oxide and aluminum oxide, Inorganic such as SrAl ₂ O ₄ : Eu, Dy, Sr ₄ Al ₁₄ O ₂₅ : Eu, Dy, CaAl ₂ O ₄ : Eu, Dy, ZnS: Cu with europium (Eu) and dysprosium (Dy) added Fluorescent materials;

Moreover, as said organic fluorescent substance, For example, organic pigments, such as a cyanine pigment, a pyridine pigment, and a rhodamine pigment | dye, Lumogen F Violet570, Copper Yellow083, Copper Orange240, Copper Red300, Daoka Chemical Industries, Ltd. made by BASF Corporation Organic dyes such as basic dye Rhodamine B, Sumiplast Yellow FL7G manufactured by Sumika Finechem Co., Ltd., MACROLEX Fluorescent Red G manufactured by Bayer, and Yellow 10GN.

As a fluorescent substance in this invention, it is preferable from a viewpoint of wavelength conversion efficiency that it is a rare earth metal complex containing an organic ligand, ie, an organic complex of rare earth metals. Especially, it is preferable from a viewpoint of wavelength conversion efficiency that it is at least 1 sort (s) of a europium complex and a samarium complex.

Moreover, there is no restriction | limiting in particular as a ligand which comprises an organic complex, According to the metal to be used, it can select suitably. Especially, it is preferable that it is a ligand which can form a complex with at least 1 sort (s) of europium and samarium.

In this invention, although it does not limit a ligand, it is preferable that it is at least 1 sort (s) chosen from carboxylic acid which is a neutral ligand, a nitrogen-containing organic compound, a nitrogen-containing aromatic heterocyclic compound, (beta) -diketones, and a phosphine oxide.

In addition, as a ligand of the rare earth metal complex, R ¹ COCHR ² COR ³ (wherein R ¹ is an aryl group, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aralkyl group or a substituent thereof, R ² is a hydrogen atom, an alkyl group, Or a cycloalkyl group, a cycloalkylalkyl group, an aralkyl group, or an aryl group, and R ³ may represent β-diketones represented by an aryl group, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aralkyl group, or a substituent thereof).

Specific examples of the β-diketones include acetylacetone, perfluoroacetylacetone, benzoyl-2-furanoylmethane, 1,3-di (3-pyridyl) -1,3-propanedione, and benzoyltrifluoro Acetone, benzoylacetone, 5-chlorosulfonyl-2-tenoyltrifluoroacetone, bis (4-bromobenzoyl) methane, dibenzoylmethane, d, d-dicamphorylmethane, 1,3-dicyano-1 , 3-propanedione, p-bis (4,4,5,5,6,6,6-heptafluoro-1,3-hexanedinoyl) benzene, 4,4'-dimethoxydibenzoylmethane, 2 , 6-dimethyl-3,5-heptanedione, dinaphthoylmethane, dipivaloylmethane, bis (perfluoro-2-propoxypropionyl) methane, 1,3-di (2-thienyl) -1 , 3-propanedione, 3- (trifluoroacetyl) -d-camphor, 6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedione, 1,1,1,2, 2,6,6,7,7,7-decafluoro-3,5-heptanedione, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5 Octanedione, 2-furyltrifluoroacetone, hexafluoroacetylacetone, 3- (hep Fluorobutyryl) -d-camphor, 4,4,5,5,6,6,6-heptafluoro-1- (2-thienyl) -1,3-hexanedione, 4-methoxydibenzoylmethane , 4-methoxybenzoyl-2-furanoylmethane, 6-methyl-2,4-heptanedione, 2-naphthoyltrifluoroacetone, 2- (2-pyridyl) benzimidazole, 5,6-di Hydroxy-1,10-phenanthroline, 1-phenyl-3-methyl-4-benzoyl-5-pyrazole, 1-phenyl-3-methyl-4- (4-butylbenzoyl) -5-pyrazole, 1-phenyl-3-methyl-4-isobutyryl-5-pyrazole, 1-phenyl-3-methyl-4-trifluoroacetyl-5-pyrazole, 3- (5-phenyl-1,3, 4-oxadiazol-2-yl) -2,4-pentanedione, 3-phenyl-2,4-pentanedione, 3- [3 ', 5'-bis (phenylmethoxy) phenyl] -1- ( 9-phenanthyl) -1-propane-1,3-dione, 5,5-dimethyl-1,1,1-trifluoro-2,4-hexanedione, 1-phenyl-3- (2-thienyl ) -1,3-propanedione, 3- (t-butylhydroxymethylene) -d-camphor, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,2,2 , 3,3,7,7,8,8,9,9,9-tetradecafluoro-4,6-nonandionone, 2,2,6,6-tetramethyl-3,5-heptane On, 4,4,4-trifluoro-1- (2-naphthyl) -1,3-butanedione, 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione , 2,2,6,6-tetramethyl-3,5-heptanedione, 2,2,6,6-tetramethyl-3,5-octanedione, 2,2,6-trimethyl-3,5-heptane Dione, 2,2,7-trimethyl-3,5-octanedione, 4,4,4-trifluoro-1- (thienyl) -1,3-butanedione (TTA), 1- (pt-butyl Phenyl) -3- (N-methyl-3-pyrrole) -1,3-propanedione (BMPP), 1- (pt-butylphenyl) -3- (p-methoxyphenyl) -1,3-propanedione (BMDBM), 1,3-diphenyl-1,3-propanedione, benzoylacetone, dibenzoylacetone, diisobutyloylmethane, dipivaloylmethane, 3-methylpentane-2,4-dione, 2, 2-dimethylpentane-3,5-dione, 2-methyl-1,3-butanedione, 1,3-butanedione, 3-phenyl-2,4-pentanedione, 1,1,1-trifluoro- 2,4-pentanedione, 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 3- Methyl-2,4-pentanedione, 2-acetylcyclopentanone, 2-acetylcyclohexanone, 1-heptafluoro Chloro-3-t-butyl-1,3-propanedione, 1,3-diphenyl-2-methyl-1,3-propanedione, or 1-ethoxy-1,3-butanedione, etc. may be mentioned. .

As the nitrogen-containing organic compound, the nitrogen-containing aromatic heterocyclic compound, and the phosphine oxide of the neutral ligand of the rare earth metal complex, for example, 1,10-phenanthroline, 2,2'-bipyridyl, 2,2 '-6,2 "-terpyridyl, 4,7-diphenyl-1,10-phenanthroline, 2- (2-pyridyl) benzimidazole, triphenylphosphineoxide, tri-n-butylforce Pin oxide, tri-n-octylphosphine oxide, tri-n-butylphosphate, and the like.

As the rare earth metal complex having the above ligand, in particular, from the viewpoint of wavelength conversion efficiency, for example, Eu (TTA) ₃ phen, Eu (BMPP) ₃ phen, Eu (BMDBM) ₃ phen or the like can be preferably used. have.

Production methods of Eu (TTA) ₃ Phen and the like are, for example, Masaya Mitsuishi, Shinji Kikuchi, Tokuji Miyashita, Yutaka Amano, J. Mater. Chem. See the method disclosed in 2003, 13, 285-2879.

In the present invention, a solar cell module having a high power generation efficiency can be configured by using a europium complex, in particular, as a fluorescent substance. The europium complex converts light in the ultraviolet region to light in the red wavelength region with high wavelength conversion efficiency, and the converted light contributes to power generation in the solar cell.

The content rate of the fluorescent substance in a wavelength convertible resin composition can be suitably selected according to the fluorescent substance and resin particle to be used. For example, it can be 0.0001-1 mass% with respect to the non volatile matter total amount (total solid content) of a wavelength conversion resin composition, It is preferable that it is 0.0001-0.1 mass%, It is more preferable that it is 0.0001-0.02 mass%.

By setting it as 0.0001 mass% or more, luminous efficiency improves more. Moreover, since it is 1 mass% or less, the fall of luminous efficiency by concentration quenching and scattering can be suppressed, and the fall of the power generation efficiency by scattering of incident light can be suppressed.

In the present invention, the fluorescent substance is at least selected from Eu (TTA) ₃ phen, Eu (TTA) ₃ Bpy, Eu (TTA) ₃ (TPPO) ₂ , Eu (BMPP) ₃ phen and Eu (BMDBM) ₃ phen As 1 type, it is preferable that the content rate is 0.0001-1 mass% with respect to the total solid of a wavelength conversion resin composition.

In the present invention, the fluorescent material is preferably used as a fluorescent material for converting wavelengths contained in resin particles described later, or a fluorescent material for converting wavelengths in which the fluorescent material is coated with a polymer dispersant. As a result, it is possible to more effectively suppress scattering of light in a wavelength region having less contribution to solar power generation.

This is because, for example, the fluorescent material having a larger refractive index than the dispersion medium resin is contained or coated in a high molecular compound (resin particles, polymer dispersant) exhibiting the same refractive index as the dispersion medium resin, whereby light scattering is more effectively suppressed. I can think of it.

(Resin particles)

The wavelength converting resin composition of this invention contains at least 1 sort (s) of resin particle. It is preferable that the said resin particle can contain the said fluorescent substance.

It is preferable that it is 1 micrometer-1000 micrometers, and, as for the primary particle diameter of the said resin particle, from a viewpoint of light utilization efficiency improvement, it is more preferable that it is 10 micrometers-500 micrometers.

The primary particle diameter of the fluorescent material for wavelength conversion can be performed using a laser diffraction scattering particle size distribution measuring apparatus (eg, Beckman Coulter, LS13320).

Moreover, there is no restriction | limiting in particular as a monomer which comprises the said resin particle, An addition polymeric monomer may be sufficient and a polycondensation monomer may be sufficient. In this invention, it is preferable that it is an addition polymeric vinyl compound from a viewpoint of stability and generation efficiency of fluorescent substance (preferably the rare earth metal complex which has an organic ligand).

Vinyl compound

In the present invention, the vinyl compound is not particularly limited as long as it is a compound having at least one ethylenically unsaturated bond, and may be a vinyl resin, particularly an acrylic resin or a methacryl resin, an acrylic monomer, a methacryl monomer, or an acryl resin when the polymerization reaction is carried out. An oligomer, methacryl oligomer, etc. can be used without a restriction | limiting in particular. In this invention, Preferably, an acryl monomer, a methacryl monomer, etc. are mentioned.

As an acryl monomer and a methacryl monomer, acrylic acid, methacrylic acid, these alkyl esters are mentioned, For example, you may use together the other vinyl compound copolymerizable with these, and can also use individually by 1 type. It is also possible to use two or more kinds in combination.

As alkyl acrylate and alkyl methacrylate, For example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid 2 Acrylic acid unsubstituted alkyl esters such as ethylhexyl and methacrylic acid unsubstituted alkyl esters; Dicyclopentenyl (meth) acrylate; Tetrahydrofurfuryl (meth) acrylate; Benzyl (meth) acrylate; (Meth) acrylate (having a number of ethylene groups of 2 to 14), trimethylolpropane di (meth) acrylate, and the like, which are obtained by reacting a polyhydric alcohol with an alpha, beta -unsaturated carboxylic acid , Trimethylol propane tri (meth) acrylate, trimethylol propane ethoxy tri (meth) acrylate, trimethylol propane propoxy tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane (Meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Bisphenol A polyoxyethylene di (meth) acrylate, bisphenol A dioxyethylene di (meth) acrylate, bisphenol A trioxyethylene di (meth) acrylate, bisphenol A A big oxyethylene di (meth) acrylate and the like); Compounds obtained by adding α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (for example, trimethylolpropanetriglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.); Esterified products of a polyvalent carboxylic acid (for example, phthalic anhydride) with a substance having a hydroxyl group and an ethylenically unsaturated group (for example, β-hydroxyethyl (meth) acrylate); Urethane (meth) acrylates (e.g., reactants of tolylene diisocyanate with 2-hydroxyethyl (meth) acrylic acid ester, trimethylhexamethylene diisocyanate, cyclohexanedimethanol and 2-hydroxyethyl (meth) acrylic acid ester Reactants, etc.); Acrylic acid substituted alkyl ester or methacrylic acid substituted alkyl ester etc. which the hydroxyl group, the epoxy group, and the halogen group etc. were substituted by these alkyl groups are mentioned.

Moreover, acrylamide, acrylonitrile, diacetone acrylamide, styrene, vinyltoluene etc. are mentioned as another vinyl compound copolymerizable with acrylic acid, methacrylic acid, an alkyl acrylate, or an alkyl methacrylate. . These vinyl monomers may be used individually by 1 type, and can be used in combination of 2 or more type.

As a vinyl compound in this invention, it is preferable to select suitably so that the refractive index of the resin particle formed may become a desired value, and it is preferable to use at least 1 sort (s) chosen from alkyl acrylate and alkyl methacrylate.

(Radical polymerization initiator)

In the present invention, in order to polymerize the vinyl compound, it is preferable to use a radical polymerization initiator. As a radical polymerization initiator, the radical polymerization initiator normally used without a restriction | limiting in particular can be used. For example, a peroxide etc. are mentioned preferably. Specifically, organic peroxides and azo radical initiators which generate free radicals by heat are preferable.

Examples of the organic oxide include isobutyl peroxide, α, α'bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxy neodecanoate, bis-n-propylperoxydicarbonate, bis-s -Butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl neodecanoate, bis (4-t-butylcyclohexyl) peroxydicarbonate, 1-cyclohexyl-1-methylethylperoxy neodecano 8, bis-2-ethoxy ethyl peroxy dicarbonate, bis (ethylhexyl peroxy) dicarbonate, t-hexyl neodecanoate, bismethoxy butyl peroxy dicarbonate, bis (3-methyl-3- methoxybutyl Peroxy) dicarbonate, t-butylperoxy neodecanoate, t-hexyl peroxy pivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide , 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic perox Id, 2,5-dimethyl-2,5-bis (2-ethylhexanoyl) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethyl Hexanoate, 4-methylbenzoylperoxide, t-butylperoxy-2-ethylhexanoate, m-toluonoylbenzoylperoxide, benzoylperoxide, t-butylperoxyisobutylate, 1,1- Bis (t-butylperoxy) 2-methylcyclohexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclo Hexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexanone, 2,2-bis (4,4 -Dibutylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy maleic acid, t-butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-bis (m-toluylperoxy) hexane, t-butylperox Isopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxy acetate , 2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t-butylperoxy iso Phthalate, α, α'bis (t-butylperoxy) diisopropylbenzene, dicumylperoxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumylperoxide, Di-t-butylperoxy-p-mentane hydroperoxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne, diisopropylbenzenehydroperoxide, t-butyltrimethylsilylperoxide , 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane Can be used.

As an azo radical initiator, For example, azobisisobutyronitrile (AIBN, V-60 (brand name, the product made by Wako Junyaku Corporation)), 2,2'- azobis (2-methylisobutyronitrile) ( V-59 (trade name, manufactured by Wako Junyaku Corporation)), 2,2'-azobis (2,4-dimethylvaleronitrile) (V-65 (brand name, manufactured by Wako Junyaku Corporation)), dimethyl-2,2 ' -Azobis (isobutylate) (V-601 (brand name, product made by Wako Junyaku Corporation)), 2,2'- azobis (4-methoxy-2, 4-dimethylvaleronitrile) (V-70 (brand name) , Wako Junyaku Co., Ltd.) etc. are mentioned.

The usage-amount of a radical polymerization initiator can be suitably selected according to the kind of said vinyl compound, the refractive index of the resin particle formed, etc., and is used by the usage-amount normally used. Specifically, it can be used in 0.01-2 mass% with respect to a vinyl compound, for example, It is preferable to use in 0.1-1 mass%.

(Fluorescent material for wavelength conversion)

The wavelength conversion material in the present invention is a fluorescent substance coated with a resin particle or a polymer dispersant containing a fluorescent substance.

These can be prepared, for example, by preparing a mixture of the fluorescent substance and a monomer compound constituting the resin particle, and polymerizing the mixture. Specifically, for example, by preparing a mixture containing a fluorescent substance and a vinyl compound, and polymerizing the vinyl compound using a radical polymerization initiator, a fluorescent substance for wavelength conversion can be constituted as the resin particle containing the fluorescent substance have.

For example, the fluorescent material for wavelength conversion formed by coating the fluorescent material with the polymer dispersant by dispersing the fluorescent material in an aqueous medium using a water insoluble polymer dispersant can be constituted.

Specifically, for example, a water-insoluble vinyl polymer dispersant comprising a hydrophilic structural unit and a hydrophobic structural unit obtained by polymerizing a vinyl compound and the fluorescent substance are coated with a vinyl polymer dispersant by dispersion treatment in an aqueous medium. The fluorescent substance for wavelength conversion can be comprised as a fluorescent substance which was made. As said dispersion processing method, a well-known dispersion processing method can be employ | adopted without a restriction | limiting in particular.

Hereinafter, as an example of the manufacturing method of the fluorescent material for wavelength conversion in this invention, the manufacturing method of the fluorescent material for wavelength conversion in which fluorescent substance was contained in the resin particle is demonstrated.

The said fluorescent material for wavelength conversion is obtained by mixing the said fluorescent substance, a vinyl compound, and radical polymerization initiators, such as a peroxide, as needed, melt | dissolving or disperse | distributing a fluorescent substance in a vinyl compound, and polymerizing this. There is no restriction | limiting in particular as a mixing method, For example, what is necessary is just to carry out by stirring.

What is necessary is just to contain content of fluorescent substance with 0.001-10 mass% with respect to a vinyl compound. More preferably, it is 0.01-1.0 mass%. By containing in this range, a fluorescent substance will melt | dissolve in a vinyl compound and can comprise the fluorescent material for wavelength conversion which is more excellent in light transmittance.

In the present invention, the vinyl compound constituting the fluorescent material for converting the wavelength is suitably so that the dispersibility of the fluorescent material for converting the wavelength with respect to the transparent dispersion medium resin becomes good when the fluorescent material for converting the wavelength after polymerization is dispersed in the dispersion medium resin. It is preferable to select.

Specifically, a state in which dispersibility is good refers to a state in which scattering that causes light loss is sufficiently suppressed in the wavelength conversion layer formed of the wavelength conversion resin composition of the present invention. Such a good state of dispersibility (state in which light scattering is suppressed) can be achieved by, for example, the following method.

The resin composition of the fluorescent material for converting wavelengths selects a mutual composition which has good dispersibility and does not cause phase separation or the like in relation to the composition of the dispersion medium resin. This can be achieved, for example, by selecting each resin composition with haze as an index.

In order to obtain a small light scattering state, a vinyl compound and a fluorescent substance in which the fluorescent substance does not precipitate may be selected in the fluorescent material for wavelength conversion before and after polymerization. For example, in the rare earth metal complex of fluorescent substance, by changing a ligand, precipitation of the fluorescent substance in a vinyl compound can be avoided and a favorable mixed state (preferably dissolved state) can be obtained.

In addition, light scattering can be reduced by lowering the concentration of a substance that causes light scattering. For example, when the fluorescent substance is caused to precipitate, the concentration of the fluorescent substance in the wavelength converting fluorescent material may be lowered. When the fluorescent substance for wavelength conversion in the transparent dispersion medium resin is caused by the fluorescent substance, do.

Preferable content rate of the said fluorescent material for wavelength conversion in the wavelength conversion resin composition of this invention is 0.0001-as a mass concentration of the organic complex (preferably europium complex) of a rare earth metal with respect to the total non volatile matter of a wavelength conversion resin composition. 1 mass% is preferable and it is more preferable that it is 0.0005-0.01 mass%.

By setting it as 0.0001 mass% or more, luminous efficiency improves more. Moreover, since it is 1 mass% or less, the fall of the luminous efficiency by concentration quenching can be suppressed, and the fall of the power generation efficiency by scattering of incident light can be suppressed.

(Dispersion medium resin)

There is no restriction | limiting in particular as a dispersion medium resin which comprises the wavelength conversion resin composition of this invention, if it is a transparent resin which can disperse | distribute the said fluorescent material for wavelength conversion, For example, photocurable resin, a thermosetting resin, a thermoplastic resin etc. It is preferably used.

Especially, it is preferable to contain the thermosetting ethylene-vinyl acetate copolymer (it is also called "EVA") currently used as sealing resin for solar cells.

In addition, in this invention, transparent sealing resin which served as a dispersion medium is not limited only to EVA, You may further contain resin other than EVA, such as a thermoplastic resin, a thermosetting resin, and a photocurable resin.

In the case where the dispersion medium resin is formed by containing the photocurable resin, the resin constitution and the photocuring method of the photocurable resin are not particularly limited. For example, in the photocuring method by an optical radical polymerization initiator, a wavelength converting resin composition is glass by (A) binder resin, (B) crosslinkable monomer, and (C) light or heat other than the said fluorescent material for wavelength conversion. It can contain a photoinitiator etc. which generate | occur | produce a radical, and can comprise.

As (A) binder resin, the copolymer which copolymerizes acrylic acid, methacrylic acid, the homopolymer which used these alkyl ester as a constituent monomer, and the other vinyl monomer copolymerizable with these as a constituent monomer can be used. . Moreover, these copolymers may be used independently and may be used in combination of 2 or more type.

Examples of the alkyl acrylate and methacrylate alkyl esters include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid 2 Unsubstituted alkyl acrylate or methacrylic acid unsubstituted alkyl ester such as ethylhexyl; Acrylic acid substituted alkyl ester, methacrylic acid substituted alkyl ester, etc. which substituted hydroxyl group, an epoxy group, a halogen group etc. with these alkyl groups are mentioned.

Examples of other vinyl monomers that can be copolymerized with acrylic acid, methacrylic acid, alkyl acrylate, and methacrylate alkyl ester include acrylamide, acrylonitrile, diacetone acrylamide, styrene, and vinyltoluene . These vinyl monomers can be used individually or in combination of 2 or more types. Moreover, it is preferable that the weight average molecular weight of (A) binder resin which comprises a dispersion medium resin is 10,000-300,000 from a point of coating film property and coating film strength.

As the (B) crosslinkable monomer, for example, a compound obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol (for example, polyethylene glycol di (meth) acrylate (the number of ethyleneoxy groups is 2 to 2). 14), trimethylolpropanedi (meth) acrylate, trimethylolpropanetri (meth) acrylate, trimethylolpropaneethoxytri (meth) acrylate, trimethylolpropanepropoxytri (meth) acrylate, tetra Methylol methane tri (meth) acrylate, tetramethylol methane tetra (meth) acrylate, polypropylene glycol di (meth) acrylate (those having 2 to 14 propyleneoxy groups), dipentaerythritol penta (meth ) Acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol A polyoxyethylenedi (meth) acrylate, bisphenol A dioxyethylenedi (meth) acrylate, bisphenol A Oxyethylene di (meth) acrylate, bisphenol A big oxyethylene di (meth) acrylate and the like); Compounds obtained by adding α, β-unsaturated carboxylic acid to a glycidyl group-containing compound (for example, trimethylolpropanetriglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc.); Esterified products of a polyvalent carboxylic acid (for example, phthalic anhydride) with a substance having a hydroxyl group and an ethylenically unsaturated group (for example, β-hydroxyethyl (meth) acrylate); Urethane (meth) acrylates (e.g., reactants of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylic acid ester, trimethylhexamethylene diisocyanate and cyclohexanedimethanol and 2-hydroxyethyl (meth) acrylic acid ester Reactants and the like).

Particularly preferred (B) crosslinkable monomers are trimethylolpropane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa, in the sense of easily controlling the crosslinking density and reactivity. (Meth) acrylate and bisphenol A polyoxyethylene dimethacrylate are mentioned. In addition, the said compound may be used independently and may be used in combination of 2 or more type.

When making refractive index of a wavelength converting resin composition especially high, it is advantageous that bromine and a sulfur atom are contained in at least 1 sort (s) of (A) binder resin and (B) crosslinkable monomer. As an example of a bromine containing monomer, Dai-ichi Kogyo Pharmaceutical Co., Ltd. product, New Frontier BR-31, New Frontier BR-30, New Frontier BR-42M, etc. are mentioned. As a sulfur containing monomer composition, Mitsubishi Gas Chemical Co., Ltd. product, IU-L2000, IU-L3000, IU-MS1010 is mentioned. However, bromine and a sulfur atom containing monomer (polymer containing it) used by this invention are not limited to what was illustrated here.

(C) As a photoinitiator, the photoinitiator which produces | generates a free radical by an ultraviolet-ray or a visible ray is preferable, For example, benzoin methyl ether, benzoin ethyl ether, benzoin propylether, benzoin isobutyl ether, Benzoin ethers such as benzoin phenyl ether, benzophenone, N, N'-tetramethyl-4,4'-diaminobenzophenone (Mihilerketone), N, N'-tetraethyl-4,4'- Benzophenones such as diamino benzophenone, benzyl dimethyl ketal (manufactured by BASF Japan, IRGACURE (irgacure) 651), benzyl ketals such as benzyl diethyl ketal, 2,2-dimethoxy-2-phenylacetophenone , acetophenones such as p-tert-butyldichloroacetophenone and p-dimethylaminoacetophenone, xanthones such as 2,4-dimethyl thioxanthone and 2,4-diisopropyl thioxanthone, or hydroxycyclo Hexylphenyl ketone (manufactured by BASF Japan, IRGACURE (irgacure) 184), 1- (4-isopropylphenyl) -2-bitoxy-2- Tilpropan-1-one (made by BASF Japan, Darocure 1116), 2-hydroxy-2-methyl-1-phenylpropan-1-one (made by BASF Japan, Darocure 1173), etc. are mentioned, These are used individually or in combination of 2 or more types.

Moreover, as a photoinitiator which can be used as (C) photoinitiator, For example, 2,4,5-triallylimidazole dimer, 2-mercaptobenzoxazole, leuco crystal violet, and tris (4- And combinations such as diethylamino-2-methylphenyl) methane. Moreover, although it does not have photoinitiation by itself, it can use the additive which becomes a sensitizer system with a good photoinitiation performance as a whole by using it in combination with the said substance, for example, tertiary amine, such as triethanolamine with respect to benzophenone. .

Moreover, in this invention, you may use a thermosetting resin instead of photocurable resin as a dispersion medium resin. As a thermosetting resin, what changed the said (C) photoinitiator to the thermal polymerization initiator can be used in the structure of photocurable resin mentioned above.

As the (C) thermal polymerization initiator, an organic peroxide which generates free radicals by heat is preferable, and isobutyl peroxide, α, α'-bis (neodecanoylperoxy) diisopropylbenzene or co Milperoxy neodecanoate, bis-n-propylperoxydicarbonate, bis-s-butylperoxydicarbonate, 1,1,3,3-tetramethylbutyl neodecanoate, bis (4-t-butylcyclohexyl Peroxydicarbonate, 1-cyclohexyl-1-methylethylperoxy neodecanoate, di-2-ethoxyethylperoxydicarbonate, bis (ethylhexylperoxy) dicarbonate, t-hexyl neodecanoate, Bismethoxybutylperoxydicarbonate, bis (3-methyl-3-methoxybutylperoxy) dicarbonate, t-butylperoxy neodecanoate, t-hexylperoxy pivalate, 3,5,5-trimethyl Hexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl perox Id, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic peroxide, 2,5-dimethyl-2,5-bis (2-ethylhexanoyl) hexane, 1-cyclo Hexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, 4-methylbenzoylperoxide, t-butylperoxy-2-ethylhexanoate, m Toluonoylbenzoyl peroxide, benzoyl peroxide, t-butylperoxy isobutylate, 1,1-bis (t-butylperoxy) 2-methylcyclohexane, 1,1-bis (t-hexylperoxy ), 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexanone, 2,2-bis (4,4-dibutylperoxycyclohexyl) propane, 1,1-bis (t-butylperoxy) cyclododecane , t-hexyl peroxy isopropyl monocarbonate, t-butyl peroxy maleic acid, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl per Silaurate, 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t- Hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxy acetate, 2,2-bis (t-butylperoxy) butane, t-butylperoxy Benzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t-butylperoxyisophthalate, α, α'bis (t-butylperoxy) diisopropylbenzene, dico Milperoxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumylperoxide, bis-t-butylperoxy-p-mentane hydroperoxide, 2,5-dimethyl -2,5-bis (t-butylperoxy) hexyne, diisopropylbenzenehydroperoxide, t-butyltrimethylsilylperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, cumene hydroperoxide , t-hexyl hydroperoxide, t-butylhydro Loperoxide, 2,3-dimethyl-2,3-diphenylbutane and the like can be used.

As the transparent dispersion medium resin of the wavelength converting resin composition of the present invention, a thermoplastic resin flowing by heating or pressurization can be used. As the thermoplastic resin, for example, natural rubber, polyethylene, polypropylene, polyvinyl acetate, polyisoprene, poly-1,2-butadiene, polyisobutene, polybutene, poly-2-heptyl-1,3-butadiene (Di) enes such as poly-2-t-butyl-1,3-butadiene, poly-1,3-butadiene, polyoxyethylene, polyoxypropylene, polyvinylethyl ether, polyvinylhexyl ether, polyvinylbutyl Polyesters such as polyethers such as ether, polyvinylacetate, polyvinyl propionate, polyurethane, ethyl cellulose, polyvinyl chloride, polyacrylonitrile, polymethacrylonitrile, polysulfone, phenoxy resin, Polyethyl acrylate, polybutyl acrylate, poly-2-ethylhexyl acrylate, poly-t-butyl acrylate, poly-3-ethoxypropyl acrylate, polyoxycarbonyl tetramethacrylate, polymethyl acrylate , Paul Isopropyl methacrylate, polydodecyl methacrylate, polytetradecyl methacrylate, poly-n-propyl methacrylate, poly-3,3,5-trimethylcyclohexyl methacrylate, polyethyl methacrylate, And poly (meth) acrylic acid esters such as poly-2-nitro-2-methylpropyl methacrylate, poly-1,1-diethylpropyl methacrylate and polymethyl methacrylate.

These thermoplastic resins may be obtained by copolymerizing two or more kinds of monomers as necessary, or may be used by blending two or more kinds of thermoplastic resins.

The thermoplastic resin may be a copolymer resin containing structural units derived from monomers such as epoxy acrylate, urethane acrylate, polyether acrylate and polyester acrylate. It is preferable that it is a copolymer resin containing the structural unit derived from a urethane acrylate, an epoxy acrylate, and a polyether acrylate especially from an adhesive point.

As an epoxy acrylate, 1, 6- hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl alcohol diglycidyl ether, resorcinol diglycidyl ether, adipic acid diglycidyl ester (Meth), such as phthalic acid diglycidyl ester, polyethylene glycol diglycidyl ether, trimethylol propane triglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, and sorbitol tetraglycidyl ether And acrylic acid adducts.

Polymers having a hydroxyl group in a molecule such as epoxy acrylate are effective for improving adhesion. These copolymerized resins can be used together 2 or more types as needed. 150 degreeC or less is preferable and, as for the softening temperature of these resins, 100 degreeC or less is more preferable. In consideration of the work environment temperature of a solar cell unit being 80 degrees C or less normally, and workability, the softening temperature of the said resin becomes like this. Preferably it is 80-120 degreeC.

The other structure of the wavelength converting resin composition in the case of using the thermoplastic resin as the transparent dispersion medium resin is not particularly limited as long as it contains the fluorescent material for converting wavelengths of the present invention, but components commonly used, for example, plasticizers and flame retardants , Stabilizers and the like can be further contained.

As a transparent dispersion medium resin of the wavelength conversion resin composition of this invention, although not restrict | limiting photocurable, thermosetting, thermoplastic, and especially resin as mentioned above, it is widely used as a transparent dispersion medium resin for conventional solar cells as especially preferable resin. The composition which mix | blended a thermal radical polymerization initiator, a crosslinking adjuvant, an adhesion | attachment adjuvant, a ultraviolet absorber, a stabilizer, etc. with ethylene-vinyl acetate copolymer (EVA) is mentioned.

The wavelength converting resin composition of the present invention is excellent in moisture resistance by using the above-mentioned fluorescent material for converting wavelengths, and the scattering of light is suppressed because the fluorescent material for converting wavelengths has good dispersibility in the transparent dispersion medium resin. Can be efficiently introduced into the solar cell.

In addition, in this invention, when "wavelength conversion fluorescent material has dispersibility in a transparent dispersion medium resin", when a fluorescent material for wavelength conversion is disperse | distributed and mixed in a transparent dispersion medium resin, the state which particle | grains and haze cannot be confirmed visually. Indicates, more specifically, the following state.

First, the fluorescent material for converting wavelengths is allowed to react so that the vinyl compound containing the fluorescent substance is polymerized. These reaction conditions can be suitably determined according to the vinyl compound to be used.

The fluorescent material for wavelength conversion is mixed with the transparent dispersion medium resin at a predetermined concentration to obtain a wavelength convertible resin composition, and the transparent dispersion medium resin is cured. Curing conditions can be suitably selected according to the transparent dispersion medium resin to be used.

Turbidity was measured using a cured wavelength converting resin composition using a haze meter (Nippon Color Industry Co., Ltd., NDH-2000), and when the turbidity was 5% or less, "The fluorescent material for converting wavelengths was contained in a transparent dispersion medium resin. Dispersibility ”.

The most important point in this invention is not only "turbidity" in the visible light region which can be measured using a haze meter as described above, but also the light absorbance of a wavelength region having a small contribution to solar power generation, for example, a fluorescent material. It was found that the light loss due to absorption and scattering at the maximum absorption wavelength in the spectrum greatly influenced the performance of the silicon crystal solar cell module of the wavelength converting resin composition, and further, the method of measurement was found. Is in point. The measuring method is described in detail below.

(Preparation of Measurement Specimen)

Although the case where EVA widely used for the solar cell module is used as a dispersion medium resin as an example of the wavelength convertible resin composition concerning this invention is described, it is not limited to this.

100 parts by mass of EVA resin (e.g., EVA resin, NM30PW manufactured by Tosoh Corporation), 2 parts by mass of TAIC (triallyl isocyanurate, manufactured by Nippon Chemical Co., Ltd.), Luperox 101 (2,5- 1.3 parts by mass of dimethyl-2,5- (t-butylperoxy) hexane and Arkema Yoshitomi Co., Ltd., a silane coupling agent SZ6030 (methacryloxypropyltrimethoxysilane, Toray Dow Corning Co., Ltd.) 0.5 mass parts, and the predetermined amount (for example, 2 mass% with respect to the total non volatile matter total amount of a wavelength converting resin composition) was mix | blended with 0.5 mass parts of manufacture), and the roll mixer which adjusted these to 90 degreeC Knead into.

The obtained kneaded material is made into the sheet-like resin composition of thickness 200-1000 micrometers by the hot press adjusted to 90 degreeC. This sheet-like resin composition is cut to an appropriate size, one side is sandwiched with slide glass and the other with PET film, and laminated using a vacuum pressurized laminator to obtain a measurement sample. Moreover, as conditions of a laminator, it carries out by hotplate 150 degreeC, pressure 100 kPa, vacuum time 10 minutes, and pressurization time 15 minutes.

On the other hand, the thing obtained in the same manner as the above except having not mix | blended the wavelength conversion fluorescent material is used as a reference sample.

(Confirmation of measurement wavelength range)

In the present invention, the measurement wavelength region can be determined by the absorbance spectrum. An absorbance spectrum can be measured by a conventional method using a spectrophotometer (For example, Hitachi High-Technology Co., Ltd. U-3310, Nippon Spectroscopy Co., Ltd. V-570, etc.). In this case, however, in addition to the original absorption depending on the fluorescent substance, in the case of the measurement sample prepared by the above-mentioned measurement sample preparation method, attention is required because there is also absorption of glass or PET serving as a base material.

In addition, in the intrinsic properties of the fluorescent substance, the peak wavelengths of the excitation spectrum and the absorbance spectrum of the fluorescence do not coincide with each other. In the present invention, the peak wavelength (maximum absorption wavelength) of the absorbance spectrum is adopted.

Moreover, in this invention, when measuring in the wavelength range including the peak wavelength (maximum absorption wavelength) of an absorbance spectrum, for example, the wavelength range of more than a maximum absorption wavelength and a raise (absorption threshold value) of an absorption spectrum Can be defined as the measurement range. The wavelength at which the absorbance spectrum is raised is taken as the wavelength at which the absorbance becomes 0.0001 (O.D./µm) or more.

(Measurement of light loss in the wavelength range of measurement)

The optical loss measurement in the measurement wavelength range is a commercially available spectrophotometer (for example, Hitachi High Technology Co., Ltd. U-3310 manufactured by Hitachi High Technology Co., Ltd.), which can irradiate a sample with monochromatic light and perform calculations automatically. In the case of using a V-570, etc., and irradiating the sample with light of all wavelengths and performing the calculation by manual operation (for example, as a light source, Solar Simulator WXS-155S-10) , And AM1.5G and the like, and measure the spectral radiant intensity by means of a diffraction grating spectroradiometer LS-100 for Solar Simulator Co., Ltd.). The former advantage is that it can be easily measured and evaluated, while the latter can also measure emission intensity.

In the present invention, but that the A ₁ (λ) value of the maximum absorption wavelength, measured in the latter than ^{3.0 × 10 -4 (OD / ㎛} ), as needed, the in the maximum absorption wavelength, measured in electron a ₂ may be evaluated by (λ) value.

<Method for Producing Wavelength Convertible Resin Composition>

As a manufacturing method of the wavelength converting resin composition of this invention, after obtaining the mixture containing a fluorescent substance and a vinyl compound (preferably at least 1 sort (s) of an acryl monomer and a methacryl monomer), the vinyl in the said mixture is obtained, for example. It can manufacture by the manufacturing method which has a process of superposing | polymerizing a monomer and obtaining a fluorescent material for wavelength conversion, and mixing the said fluorescent material for wavelength conversion with a transparent dispersion medium resin, and obtaining a wavelength convertible resin composition.

(Step of Obtaining Fluorescence Material for Wavelength Conversion)

The mixture containing a fluorescent substance and a vinyl compound is obtained by mixing radical polymerization initiators, such as a peroxide, a chain transfer agent, etc. in addition to a fluorescent substance and a vinyl compound. There is no restriction | limiting in particular as a mixing method, For example, what is necessary is just to carry out by stirring with an ultrasonic mixing, a mixing rotor, a magnetic stirrer, and a stirring blade.

The fluorescent material for wavelength conversion can be obtained by polymerizing the vinyl compound in the obtained mixture. As polymerization conditions, it can select suitably according to the vinyl compound and radical polymerization initiator to be used, and what is necessary is just to adjust suitably with reference to normal polymerization conditions.

The state of the produced polymer (fluorescence material for wavelength conversion) can be selected according to the glass transition temperature. In a high glass transition temperature, for example, methyl methacrylate etc., surfactant is added to the water which kept the liquid which mixed fluorescent substance and a radical polymerization initiator at predetermined temperature, and suspended here, and a particulate polymer is suspended. It can be obtained (suspension polymerization). Moreover, finer particle | grains can also be obtained by making it suspend more finely by changing the kind of surfactant suitably (emulsification polymerization).

Moreover, butyl acrylate etc. which have a glass transition point lower than room temperature can superpose | polymerize the liquid which mixed fluorescent substance and radical polymerization initiator as it is in a container, such as a flask, and can obtain a high viscosity polymer.

As a radical polymerization initiator, organic peroxides, such as lauroyl peroxide, are preferable, for example, and when it is lauroyl peroxide, it is good to superpose | polymerize at 50-60 degreeC.

(Step of Obtaining Wavelength Convertible Resin Composition)

By converting the obtained fluorescent material for wavelength conversion into a transparent dispersion medium resin, a wavelength convertible resin composition can be produced.

Mixing conditions can be suitably selected according to the fluorescent material for wavelength conversion and transparent dispersion medium resin. For example, when using an ethylene-vinyl acetate copolymer as a transparent dispersion medium resin, a roll mill can be used. Specifically, it is obtained by kneading by adding a fluorescent polymerization material, a radical polymerization initiator, a silane coupling agent, and other additives to a pellet or powdery ethylene-vinyl acetate copolymer to a roll adjusted to 90 ° C., if necessary. Lose.

The wavelength conversion resin composition of this invention obtained as mentioned above can be used as a light transmissive layer of a solar cell module. Although the form of wavelength converting resin composition does not have a restriction | limiting in particular, It is preferable to form in sheet form from the point of ease of use. In order to make a sheet form, it can form through a spacer by the press machine adjusted to 90 degreeC. When the thickness of the spacer is about 0.4 to 1.0 mm, an easy-to-use sheet-like wavelength converting resin composition is obtained.

Moreover, you may emboss on the sheet surface. By carrying out the embossing process, bubbles can be reduced from being swept away in the process of manufacturing the solar cell module.

Moreover, the wavelength conversion resin composition obtained as mentioned above may be formed in the cast film form, affixed inside the solar cell or protective glass, and may comprise at least 1 layer of the light transmissive layer of a solar cell module. have.

The wavelength conversion resin composition for use in a cast film is obtained by mix | blending a crosslinkable monomer, light, or a thermal initiator suitably with the acrylic resin superposed | polymerized in solutions, such as toluene, and mixing it with the said fluorescent material for wavelength conversion.

The liquid mixture of this wavelength converting resin composition is apply | coated on the film used as a base material (for example, PET film) using an applicator etc., and a solvent is dried and a cast film is obtained.

The wavelength converting resin composition of the present invention can be used as one light transmitting layer of a solar cell module having a plurality of light transmitting layers.

The solar cell module is composed of necessary members such as an antireflection film, a protective glass, a sealing material, a solar cell, a back film, a cell electrode and a tab wire, for example. As a light transmissive layer which has a light transmittance among these members, an anti-reflective film, a protective glass, a sealing material, the SiNx: H layer, Si layer of a solar cell, etc. are mentioned.

It is preferable to use the wavelength conversion resin composition of this invention as a sealing material among the said light transmissive layers. Moreover, it can also arrange | position as a film for wavelength conversion between a protective glass and a sealing material, or between a sealing material and a solar cell.

When using a wavelength converting resin composition as a light transmissive layer, it is preferable that a transparent dispersion medium resin is at least about the same as that of the incident side layer, or is high refractive index.

Specifically, the plurality of light transmissive layers are formed from layers 1, 2, ... from the light incident side. , Layer m, and their refractive indices are n ₁ , n ₂ ,. When n _m , n ₁ ≤ n ₂ ≤. It is preferable that ≤ n _m be established.

In the present invention, the stacking order of the light transmissive layer exemplified above is usually an antireflection film, a protective glass, a sealing material, and a SiNx: H layer of a solar cell, which are normally formed in order from the light receiving surface of the solar cell module. , Si layer.

That is, when using the wavelength converting resin composition of this invention as a sealing material, in order to introduce external light which enters from a light receiving surface into a solar cell efficiently with little reflection loss, the refractive index of a wavelength converting resin composition is the wavelength The light transmissive layer disposed on the light incidence side than the convertible resin composition, that is, higher than the refractive index of the antireflection film, protective glass, etc., and disposed on the anti-light incidence side of the sealing material comprising the wavelength converting resin composition of the present invention. It is preferable to make it lower than refractive index of a light transmissive layer, ie, the SiNx: H layer (it is also called a "cell antireflection film") of a solar cell, and a Si layer.

When using the wavelength conversion resin composition of this invention as a sealing material, it is arrange | positioned on the light receiving surface of a solar cell. By doing so, it can follow the uneven | corrugated shape containing the texture structure of a solar cell light receiving surface, a cell electrode, a tab wire, etc. without a gap.

<Solar cell module>

The solar cell module of this invention is provided with the light transmitting layer containing the said wavelength converting resin composition. As a result, excellent conversion efficiency can be achieved.

The solar cell module can be manufactured as a wavelength conversion type sealing material, for example between a solar cell and a protective glass using the sheet-like resin composition layer obtained using the wavelength convertible resin composition of this invention.

Specifically, the solar cell module can be configured according to a conventional method for producing a silicon crystal solar cell module, and a layer (particularly preferably in the form of a sheet) made of the wavelength converting resin composition is used in place of the usual sealing material sheet. Thereby, the solar cell module of this invention can be manufactured.

In general, a silicon crystal solar cell module first puts a sheet-like sealing material (mostly obtained by thermosetting polymerization of an ethylene-vinyl acetate copolymer by a thermal radical polymerization initiator) on a cover glass which is a light receiving surface. In this invention, the wavelength conversion resin composition of this invention is used for the sealing material used here. Next, the cell connected by the tab wire is put, and the sheet-shaped sealing material (however, in this invention, a wavelength converting resin composition may be used only for the light receiving surface side, and this back surface may be conventional). It mounts, and also a back seat | sheet is set as a module using the vacuum pressurization laminator for solar cell modules.

At this time, the hot plate temperature of the laminator is a temperature necessary for the sealing material to soften and melt, to enclose the cell, and to harden, and is usually 120 to 180 ° C., most of which are physical changes and chemical changes at 140 to 160 ° C. Is designed to happen.

The wavelength convertible resin composition of this invention is a thing before the solar cell module, and when a curable resin is used, it says a semi-cured state. In addition, the refractive index of the layer which consists of a wavelength convertible resin composition of a semi-hardened state, and the layer after hardening (after solar-modulating) does not change large.

Moreover, when using it as a cast film form, when using a wavelength converting resin composition, it laminates using a vacuum laminator on the semi-light incident surface of protective glass or the light incident surface of a solar cell first, and removes a base film. If it is photocurable, it hardens | cures by light irradiation. If it is thermosetting, it is cured by applying heat, which may be cured simultaneously by applying heat during lamination. The following process can be performed according to the conventional manufacturing method of a solar cell module.

<Evaluation method of wavelength convertible resin composition>

The evaluation method of the wavelength converting resin composition for solar cells of this invention is a wavelength converting resin composition for solar cells containing the fluorescent substance whose maximum absorption wavelength in (lambda) an absorption spectrum is (lambda) _max (nm), and a dispersion medium resin, Nm) and the incident light having the light intensity of I ₀ (λ) in the thickness direction of the resin film having a thickness of t (μm) formed of the resin composition is I (λ), and the intensity of transmitted light is obtained. The maximum absorption when the intensity of transmitted light obtained by incident in the thickness direction of the reference resin film having a thickness of t _ref (μm) formed from the resin composition for reference except the fluorescent substance is I _ref (λ). based on a value of a ₁ (λ) represented by the following formula (1) at a wavelength of λ _max (㎚) involves assessing the wavelength conversion efficiency.

Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref

In the present invention, the wavelength conversion efficiency of the solar cell wavelength conversion-sensitive resin composition is evaluated based on the value of the A ₁ (λ). Specifically, by comparing the predetermined reference value, and the A ₁ (λ), it is determined that the A ₁ (λ) is excellent in wavelength conversion efficiency to or less than the reference value. In this invention, the said reference value can be 3.0 * 10 <^-4> (OD / micrometer), for example, It is preferable that it is 2.5 * 10 <^-4> (OD / micrometer), and it is 2.0 * 10 <^-4> (OD /) More preferably).

By evaluating the wavelength conversion efficiency of the wavelength conversion resin composition for solar cells by such an evaluation method, the wavelength conversion resin composition for solar cells which is excellent in conversion efficiency can be screened without actually configuring a solar cell.

Further, as described already described for the details of the A ₁ (λ).

As for the indication of the Japanese application 2010-090350, the whole is taken in into this specification by reference.

All documents, patent applications, and technical specifications described herein are incorporated by reference herein to the same extent as if the individual documents, patent applications, and technical specifications were specifically and individually described. Is brought in.

Example

Hereinafter, the present invention will be described concretely with reference to Examples, but the present invention is not limited to these Examples. In addition, "part" and "%" are mass references | standards unless there is particular notice.

&Lt; Synthesis of fluorescent substance &gt;

200 mg of 4,4,4-trifluoro-1- (thienyl) -1,3-butanedione (TTA) is dissolved in 7 ml of ethanol, to which 1.1 ml of 1 M sodium hydroxide is added and mixed To obtain a mixed solution. Subsequently, 6.2 mg of 1,10-phenanthroline dissolved in 7 ml of ethanol was added to the previous mixture, followed by stirring for 1 hour. Then, 103 mg of EuCl ₃ · 6H ₂ O was dissolved in 3.5 ml of water. Was added to obtain a precipitate. The obtained precipitate was separated by filtration, washed with ethanol and dried to obtain a fluorescent substance Eu (TTA) ₃ Phen.

<Manufacture 1 of the fluorescent material for wavelength conversion-suspension polymerization->

0.5 part of Eu (TTA) ₃ Phen obtained above as a fluorescent substance, 100 parts of methyl methacrylate as a vinyl compound, 0.2 parts of lauroyl peroxide as a radical polymerization initiator, and 0.1 parts of n-octanethiol as a chain transfer agent. Then, these were mixed and stirred to prepare a monomer mixed liquid.

Furthermore, 0.036 parts of polyvinyl alcohol was added to 500 parts of ion-exchange water as surfactant, the monomer mixture liquid mentioned above was added here, and it stirred violently with a homogenizer. The suspension was subjected to suspension polymerization using a reflux tube and a flask under a nitrogen stream while maintaining the temperature at 60 ° C, and finally heated to 90 ° C to complete the polymerization reaction.

The fluorescent material for wavelength conversion obtained here became a particle shape with an average diameter of about 100 micrometers, this was filtered and dried, and it screened as needed, and the fluorescent material for wavelength conversion was obtained.

In addition, the average diameter of the fluorescent material for wavelength conversion was measured as volume average particle diameter using LS13320 by the Beckman Coulter company as a particle size distribution meter using water as a dispersion medium.

<Production 2 of the fluorescent material for wavelength conversion-emulsion polymerization->

0.3 parts of Eu (TTA) ₃ Phen obtained above as a fluorescent substance, 60 parts of methyl methacrylate as a vinyl compound, and 0.012 parts of n-octanethiol as a chain transfer agent were mixed and stirred to prepare a monomer mixture solution.

3.65 parts of sodium alkylbenzenesulfonate (G-15, manufactured by Cao) was added as a surfactant to 300 parts by mass of ion-exchanged water. The monomer mixture liquid mentioned above was added to this, it stirred at the reflux tube and the flask under nitrogen stream, it hold | maintained at 60 degreeC, 0.03 mass part of potassium persulfate was added as a radical polymerization initiator, emulsion polymerization was performed for 4 hours, Finally, it heated up at 90 degreeC and completed the polymerization reaction.

The fluorescent material for wavelength conversion obtained here becomes a particulate form with a primary particle diameter of about 100 nm, post-treatment is performed suitably with isopropyl alcohol, etc., this is filtered-separated and dried, and it performs a sieve as needed, and performs fluorescent conversion for wavelength conversion. Obtained the material.

(Examples 1 to 22)

<Preparation of wavelength convertible resin composition>

100 parts of ethylene-vinyl acetate resin: NM30PW (manufactured by Tosoh Corporation) as a transparent dispersion medium resin, and a peroxide thermal radical polymerization initiator: Luperox 101 (manufactured by Arkema Yoshitomi Corporation, in this case also act as a crosslinking agent) Part, silane coupling agent: 0.5 parts of SZ6030 (manufactured by Toray Dow Corning Co., Ltd.) and the type and amount of the fluorescent material for wavelength conversion after polymerization obtained as described above are appropriately changed as shown in Table 1 (wavelength conversion About one fluorescent material for fluorescent substance corresponded to 0.005 parts), and it knead | mixed with the roll mill of 90 degreeC, and obtained the resin composition for wavelength conversion, respectively.

<Manufacture of the wavelength conversion type sealing material sheet using the resin composition for wavelength conversion>

The wavelength conversion type sealing material sheet which changed the thickness suitably was obtained by sandwiching the resin composition for wavelength conversion obtained above by the mold release sheet, using the stainless steel spacer, and using the press which adjusted the hotplate to 90 degreeC.

<Production of Specimens for Evaluation>

The wavelength conversion type sealing material sheet obtained above was placed on a glass plate, and a PET film was placed thereon, using a vacuum pressurized laminator (NPC, LM-50x50-S) for solar cells, hot plate 150 deg. The specimen for evaluation was produced on the conditions of 15 minutes of pressurization.

<Evaluation 1 of excitation wavelength region light loss>

The evaluation sample obtained above was mounted on the detection part of the diffraction grating type | mold spectroradiometer LS-100 for the solar simulator manufactured by Eiko Seiki Co., Ltd., and the solar simulator WXS-155S-10 by AM1.5G was manufactured. Light was irradiated and the intensity spectrum I ((lambda)) was obtained.

Further, nothing was placed on the detection unit of the LS-100 to obtain a blank intensity spectrum I ₀ (λ). In the preparation of the specimen for evaluation, the reference specimen prepared without using the wavelength conversion fluorescent material was placed on the detection unit of the LS-100 to obtain the intensity spectrum I _ref (λ) of the reference specimen.

Moreover, the thickness of the thickest part of the evaluation sample and the reference sample was measured using the digital micrometer, and the thickness t and t _ref of each were obtained by subtracting the thickness of glass and PET film. The spectrum of A ₁ (λ) was obtained by the following equation. It represents an example of the spectrum of the product A ₁ (λ) in Figs. 3 enlarges a part of FIG.

A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref

<Confirmation of excitation wavelength region>

The excitation spectrum was measured using a spectrophotometer and Hitachi High Technology Co., Ltd. F-4500 with respect to the fluorescent substance solution which melt | dissolved the fluorescent substance obtained above in isopropyl alcohol. An example of an excitation spectrum is shown in FIG.

Moreover, about the wavelength conversion type sealing material sheet containing a fluorescent substance, the absorbance spectrum was measured using the Nippon Spectrophotometer Co., Ltd. spectrophotometer V-570. An example of an absorbance spectrum is shown in FIG.

In these figures, the excitation peak wavelength is around 390 nm, and the absorption peak wavelength is shifted by 350 m. Thus, in the present Example and the comparative example, the above-mentioned A ₁ (λ) at 350 nm which is the maximum absorption wavelength is evaluated. It was.

In addition, the absorption threshold value at which the absorbance per film thickness in the absorbance spectrum is 1.0 × 10 ⁻⁴ (OD / μm) or less is about 400 nm, and also about the average value of A ₁ (λ) of 350 to 400 nm. Evaluation was performed.

Table 1 shows the average value of A ₁ (350 nm) and A ₁ (350 to 400 nm).

<Evaluation of Solar Cell Module>

Hitachi Chemical Industry Co., Ltd. solar cell conductive film, CF-105, was used for a silicon crystal solar cell, and the tab wire (thickness 0.14 mm, width 2 mm, galvanized) was measured by a dedicated crimping device. Two rows of back sides were connected, and each of these front and back was used as an external blower wire using the horizontal tap wire (The Hitachi Electric Wire Co., Ltd. make, A-TPS 0.23 * 6.0). Solar cell IV according to JIS-C-8914 using the Wakomu Electric Solar Co., Ltd. solar simulator WXS-155S-10, AM1.5G, and the IV curve tracer MP-160 for the Aiko Seiki Co., Ltd. solar simulator. Properties were obtained.

Moreover, using this silicon wire type | mold solar cell connected with the tab wire, the wavelength conversion type obtained by the cover glass (Asahi Glass Co., Ltd. product) and the said <production of the wavelength conversion type sealing material sheet using the wavelength conversion resin composition> from the bottom. Sealing material (EVA) sheet, said solar cell, EVA sheet for back surface (does not contain fluorescent material), PET film (Toyobo ester film A4300 manufactured by Toyo Spinning Co., Ltd.), and vacuum pressurized laminator for solar cells ( The solar cell module for evaluation was manufactured on the conditions of hotplate 150 degreeC, 10 minutes of vacuum, and 15 minutes of pressurizations using NPC, LM-50x50-S. About the obtained solar cell module for evaluation, the solar cell I-V characteristic was obtained by the same method as the above. The obtained result was put together in Table 1.

The solar cell module for evaluation was evaluated using (DELTA) Jsc calculated by the following formula regarding Jsc (short-circuit current density) among various measured values.

ΔJsc = Jsc (module)-Jsc (cell)

However, in the evaluation here, it measured without using the UV filter of a solar simulator.

Further, the relationship expressed with the ΔJsc A ₁ (350 ㎚) in Fig. From these figures, the larger the value of A ₁ (λ _max) it can be seen that the wavelength conversion effect of the solar cells disappear.

In addition, it exhibited a mean value of the relationship of the ΔJsc and A ₁ (350 ~ 400 ㎚) in Fig. From these figures, the larger the average value of A ₁ (350 ~ 400 ㎚) it can be seen that the wavelength conversion effect of the solar cells disappear.

(Comparative Examples 1 to 3)

<Preparation of the resin composition for wavelength conversion> of Examples 1-22 WHEREIN: Instead of using the fluorescent material for wavelength conversion, the addition amount was suitably changed so that content of the fluorescent substance itself obtained above may become content shown in Table 1. In the same manner to the above, the resin composition for wavelength conversion was obtained.

For the obtained resin composition for use in wavelength conversion, in the same manner as described above it was calculated the value A ₁ (λ).

Moreover, the solar cell module for evaluation was produced similarly to the above, and the performance was evaluated. The evaluation results are shown in Table 1.

<Evaluation of the Linear Transmittance in the Visible Region>

About the sample for evaluation of the Example and comparative example which were obtained above, the linear transmittance | permeability (PT) in a visible region is measured using a haze meter (made by Nippon Denki Color Industry Co., Ltd., NDH-2000), and its commercial log The index log ₁₀ PT / t obtained by dividing by the thickness (t) of the sample for evaluation was normalized to the film thickness.

These results are summarized in FIG. 7 shows no correlation between the index log ₁₀ PT / t and ΔJsc, and it is understood that the visible light transmittance is not sufficient to show the wavelength conversion effect in the solar cell.

<Evaluation of luminescence intensity>

The integrated emission intensity was measured using the light emission quantum efficiency measuring apparatus (Systems Engineering Co., Ltd., QEMS-2000) about the sample for evaluation of the Example and comparative example obtained above.

These results are summarized in FIG. It is understood from FIG. 8 that there is no particular correlation between the integrated emission intensity and ΔJsc, and that the integrated emission intensity is not sufficient to exhibit the wavelength conversion effect in the solar cell.

Industrial availability

According to the present invention, when the wavelength converting fluorescent material and the wavelength converting resin composition are applied to a solar cell module, the incident light converts light having a small contribution to solar power generation to a wavelength having a large contribution to power generation. The resin composition for wavelength conversion which can utilize sunlight light efficiently and stably without deterioration can be provided.

Claims (6)

As a resin composition containing the fluorescent substance whose maximum absorption wavelength in an absorbance spectrum is (lambda) _max (nm), resin particle, and a dispersion medium resin,
A wavelength λ (㎚) to I (λ) the intensity of the transmission light obtained by the light intensity is incident to the incident light is I ₀ (λ) in the resin composition is a resin film thickness direction and having a thickness of t (㎛) formed by in, and
The intensity of the transmitted light obtained when the incident light is incident from the resin composition in the thickness direction of the reference resin film having a thickness of t _ref (μm) formed of the reference resin composition excluding the fluorescent substance and the resin particles is defined as I _ref (λ). If the,
The formula, the value of A ₁ (λ) represents 3.0 to 1 in the maximum absorption wavelength ^{_{λ max (㎚) × 10 -4}} (OD / ㎛) or less solar cell wavelength conversion-sensitive resin composition.
Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref The method according to claim 1,
The fluorescent substance is a wavelength converting resin composition for solar cells contained in the resin particles. The method according to claim 1,
The fluorescent substance is a wavelength converting resin composition for a solar cell which is a rare earth metal complex containing an organic ligand. 3. The method of claim 2,
The fluorescent substance is a wavelength converting resin composition for a solar cell which is a rare earth metal complex containing an organic ligand. The solar cell module provided with the light transmissive layer containing the wavelength convertible resin composition for solar cells in any one of Claims 1-4. As an evaluation method of the wavelength converting resin composition for solar cells containing the fluorescent substance whose maximum absorption wavelength in a absorbance spectrum is (lambda) _max (nm), and a dispersion medium resin,
A wavelength λ (㎚) to I (λ) the intensity of the transmission light obtained by the light intensity is incident to the incident light is I ₀ (λ) in the resin composition is a resin film thickness direction and having a thickness of t (㎛) formed by in, and
In the case where the intensity of the transmitted light obtained by inciting the incident light from the resin composition in the thickness direction of the reference resin film having a thickness of t _ref (μm) formed from the resin composition for reference except the fluorescent substance is I _ref (λ),
The maximum absorption wavelength λ _max (㎚) of the formula 1 ₁ A solar cell wavelength conversion Evaluation methods of the resin composition, comprising: evaluating the wavelength conversion efficiency on the basis of the value of (λ) represented by In.
Equation 1: A ₁ (λ) = {log (I ₀ (λ) / I (λ))} / t-{log (I ₀ (λ) / I _ref (λ))} / t _ref

Images